The ability to distinguish between different types of tissue, whether normal or abnormal, in Magnetic Resonance Imaging (MRI) is dependent upon the image contrast achievable between tissues. MR Microscopy experiments are being performed at increasingly higher Bo field strengths to achieve acceptable signal to noise ratios (SNR) at higher resolutions. The usual contrast parameters are T1 and T2, but as Bo is increased, other studies have shown that T1 values in tissue may converge, and T2 values becomes very short. Other parameters that give better contrast between tissue types are therefore of interest. The purpose of this study, is to investigate other potential contrast parameters, such as T1r (spin locking), or Magnetization Transfer Contrast (MTC). Experiments will begin with various non-biological phantoms, such as agarose gels of various concentrations, and will progress towards using rodent tissues, such as rat kidneys, guinea pig kidneys, rat brains, etc., obtained as excess from other experimenters. Some of the study may involve using human cartilage specimens that have been used in another experiment.